The invention relates generally to air conditioning devices, and more particularly it relates to a device for air conditioning a room provided with a double pane glass window and with an air outlet spaced apart from the inner pane and communicating with the outlet channel between the outer pane and the inner pane of the window, including a sun drape arranged in the room opposite the inner pane.
An air conditioning device of this type is described in the German publication DE-OS No. 23 31 332. In this prior art device, warm air from the space to be air conditioned or air from an independent air exhausting system is introduced through an array of slits into the air outlet channel in such a manner that a relatively thin film or layer of air flows from below and propagates along the inner surface of the outer pane whereas the remaining air in the outlet channel is brought into motion by the movement of the air film and forms a slightly turbulent flow along the surface of the inner pane. This arrangement is supposed to achieve a high heat insulating effect. By using a reflection glass for the outer and inner panes or a sun drape, an anti-glare effect is achieved. The clearance of the channel between the outer and inner panes in this known device as well as in the remaining prior art solutions is about 200 mm.
These known air conditioning devices possess, however, the following disadvantages:
Air supplied in a closed ventilated or air-conditioned space has to be pretreated (by warming up, drying and the like) and this pretreatment is expensive. In order to save expensive energy attempts have been made to reduce the amount of the supplied fresh air to a minimum. When taking into account different uses of the spaces to be ventilated or air conditioned, the location of these spaces and so on, there result definite values for such minimum flows of fresh air. For example, if a space to be air conditioned is used by smokers, the minimum rate of flow of fresh air per each smoker is computed to be about 42 cubic meters per hour. For a non-smoker this minimum value is only 8.5 cubic meters per hour, for example. The above exemplary values for the minimum flow rate of the fhres air determine the overall design of the air conditioning installation.
As a rule, about 50 to 100 cubic meters of air per hour and per meter of the window width are required for the necessary minimum amount of the fresh air.
For the different amounts of air to be supplied within the predetermined limits, the known air conditioning devices of this type do not achieve well-defined air flows in the relatively wide air outlet channel. In such prior-art devices the air flows into the outlet channel through slots and the like from below and due to the relatively large clearance of the channel the flow becomes turbulent in an uncontrollable manner. Inasmuch as under any circumstances the vapor condensation on the inner surface of the outer pane has to be prevented, and since such a condensation in the air outlet channel by the air flow itself cannot be avoided because of the relatively low speed of the flow in the channel and particularly due to the completely uncontrollable turbulences of the flow, experts in the art concentrated on the effort to further improve the insulating qualities of the outer pane. This solution, however, further increases the already substantial cost of such known devices.
Another disadvantage of known windows in this device is their relatively large structural depth resulting from the large spacing between the inner and outer panes. The excessive depth of the structure diminishes the utilizable inner space to be air conditioned and consequently brings about a further increase in the construction costs.
Especially in summer when an increased sun radiation takes place the known air-conditioning devices have the following further disadvantage: As known, if a sun ray beam passes through a medium, a certain portion of the ray beam is reflected from the upper surface of the medium whereas the portion of the ray beam which enters the medium is refracted and absorbed whereby the medium heats up. Only a negligible portion of the sun rays impinging on the outer pane is reflected whereas the majority of the rays enter the air outlet channel whereby as a result of absorption the outer pane as well as the air in the air outlet channel are subject to heating. The incoming sun rays are partially reflected on the outer side of the inner pane and contribute to an additional heating of the air in the outlet as well as to the heating of the outer pane. The part of sun rays passing through the inner pane are partially reflected by the sun drape and thus impinge against the outer surface of the inner pane and result anew into the heating of the latter.
For this reason a general interpretation among experts is that the provision of sun drape opposite the inner pane of the window in the space to be air conditioned results in the worst sun screening factor. As the best heat inhibiting means is considered the arrangement of the sun drape on the open air side opposite the outer pane (DE-Z "Bauen+Wohnen", copy 2/3, 1976, pages 72 and 73). Accordingly, the use of a strip-like or laminated drape between the window panes as well as in the interior of the room is explicitly not recommended due to allegedly insufficient protection against sun heat (CH-Z "Schweizerische Bauzeitung" 93rd annular publication, 1946, page 741).